US11933896B2 - Optical distance measuring apparatus - Google Patents

Optical distance measuring apparatus Download PDF

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US11933896B2
US11933896B2 US17/061,239 US202017061239A US11933896B2 US 11933896 B2 US11933896 B2 US 11933896B2 US 202017061239 A US202017061239 A US 202017061239A US 11933896 B2 US11933896 B2 US 11933896B2
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pulse width
light
peak
histogram
pulse
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US20210018624A1 (en
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Yoshihide Tachino
Isamu Takai
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Denso Corp
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Denso Corp
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
    • G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
    • G01S7/4866—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak by fitting a model or function to the received signal

Definitions

  • the present disclosure relates to optical distance measuring apparatuses.
  • a known optical distance measuring apparatus measures the distance of a target object relative to the apparatus using light.
  • An optical distance measuring apparatus includes a histogram generator, a peak detector, and a distance calculator.
  • the histogram generator records, every predetermined period, a frequency representing the number of pulse signals outputted from at least one light receiver to thereby generate a histogram.
  • the peak detector detects, from the histogram, an edge point of at least one peak figure included in the histogram.
  • the distance calculator subtracts, from a time indicative of the edge point of the at least one peak figure, a time length of the second pulse width to thereby calculate a target time.
  • the distance calculator calculates a distance to the target object as a function of the calculated target time.
  • FIG. 1 is a diagram illustrating a schematic configuration of an optical distance measuring apparatus
  • FIG. 2 is a diagram illustrating a schematic configuration of a light receiver
  • FIG. 3 is a graph illustrating an example of a histogram
  • FIG. 4 is graph illustrating histograms respectively generated based on different intensity levels of incident light
  • FIG. 5 is a graph illustrating a histogram according to the second embodiment
  • FIG. 6 is a graph illustrating a peak detection method according to the third embodiment
  • FIG. 7 is a diagram illustrating a first example of an adjuster according to the fourth embodiment.
  • FIG. 8 is a graph illustrating a method of adjusting a second pulse width according to the fourth embodiment.
  • FIG. 9 is a diagram illustrating a second example of the adjuster according to the fourth embodiment.
  • FIG. 10 is a diagram illustrating a third example of the adjuster according to the fourth embodiment.
  • FIG. 11 is a diagram illustrating a modified configuration of the light receiver.
  • FIG. 12 is a graph illustrating a pulse signal outputted from the light receiver illustrated in FIG. 11 .
  • Japanese Patent Application Publication No. 2016-176750 discloses an optical distance measuring apparatus.
  • the disclosed optical distance measuring apparatus which includes the array of single photon avalanche diodes (SPADs) and an adder, calculates, using the adder, the sum of pulse signals respectively outputted from some diodes included in the array of the SPADs; each of the diodes outputs the corresponding pulse signal that depends on corresponding incident light that is reflected light from a target object.
  • SPADs single photon avalanche diodes
  • the disclosed optical distance measuring apparatus records, as a frequency, the calculated sum of the pulse signals every predetermined period to thereby generate a histogram.
  • the disclosed optical distance measuring apparatus thereafter detects, in the histogram, a peak representing the maximum value selected in the frequencies, and calculates the distance of the target object relative to the apparatus in accordance with the time of occurrence of the peak.
  • Japanese Patent Publication No. 5644294 is also cited as a reference document to this application.
  • the inventors of the present disclosure have considered how to improve the measurement accuracy of such an optical distance measuring apparatus to thereby gain a new insight that the time of occurrence of the peak in the histogram varies depending on the intensity of incident light.
  • the inventors of the present disclosure have found, based on their insight, that calculation of the distance of a target object relative to the optical distance measuring apparatus using the time of occurrence of the peak may cause the calculation result to vary depending on change of the intensity of incident light, resulting in the measurement accuracy of the optical distance measuring apparatus deteriorating.
  • the present disclosure can be implemented as an exemplary aspect described hereinafter.
  • the exemplary aspect of the present disclosure provides an optical distance measuring apparatus.
  • the optical distance measuring apparatus includes a light source configured to irradiate a target object with at least one light pulse having a first pulse width, and at least one light receiver configured to output a pulse signal.
  • the output signal represents reflection light from the target object being incident on the at least one light receiver, and has a second pulse width that is larger than or equal to the first pulse width.
  • the optical distance measuring apparatus includes a histogram generator configured to record, every predetermined period, a frequency representing the number of pulse signals outputted from the at least one light receiver to thereby generate a histogram.
  • the optical distance measuring apparatus includes a peak detector configured to detect, from the histogram, an edge point of at least one peak figure included in the histogram.
  • the optical distance measuring apparatus includes a distance calculator configured to subtract, from a time indicative of the edge point of the at least one peak figure, a time length of the second pulse width to thereby calculate a target time, and calculate a distance to the target object as a function of the calculated target time.
  • the apparatus is configured such that the second pulse width of the pulse signal outputted from the at least one light receiver is larger than or equal to the first pulse width of the at least one light pulse transmitted from the light source.
  • This configuration enables subtraction of the time length of the second pulse width from the edge point of the at least one peak figure included in the histogram to accurately calculate, as the target time, an incident time of the reflection light on the at least one light receiver. Calculating the distance to the target object based on the calculated incident time therefore enables the distance to the target object to be accurately obtained independently of the intensity of the reflection light incident on the at least one light receiver.
  • the optical distance measuring apparatus 1 includes a light source 20 , a light-receiver array 30 , a sum calculator 40 , a histogram generator 50 , a peak detector 60 , and a distance calculator 70 .
  • Each of the sum calculator 40 , histogram generator 50 , peak detector 60 , and distance calculator 70 can be designed as an electronic circuit.
  • One or more unillustrated central processing units (CPUs) can carry out one or more programs to thereby implement these components 40 , 50 , 60 , and 70 as software-based components.
  • the optical distance measuring apparatus 10 is for example installed in a vehicle and used for detection of obstacles and for cruise assistance of the vehicle.
  • the light source 20 serves as an apparatus that irradiates a target object OB with light for measurement of the distance to the target object OB relative to the apparatus 10 .
  • the light source 20 of the first embodiment for example includes a laser diode device 21 .
  • the laser diode device 21 is driven to transmit pulsed laser light, i.e. laser light pulses, each of which has a first pulse width PW 1 . That is, the laser diode device 21 is configured to transmit a laser light pulse every predetermined period.
  • the light source 20 of the first embodiment which is comprised of the laser diode device 21 , can be comprised of another light emitting device, such as a solid-state laser device.
  • the light receiver array 30 includes light receivers 31 ; each of the light receivers 31 is capable of outputting a pulse signal in response to receiving reflected light from the target object OB.
  • Each of the light receivers 31 is configured as a known circuit comprised of, for example, an avalanche photodiode 32 serving as a light receiving device, a quench resistor device 33 , and an inverter, i.e. a NOT gate, 34 .
  • each light receiver 31 is configured such that the avalanche photodiode 32 and quench resistor device 33 are connected in series between a power source and a grounded line, and a connection point between the avalanche photodiode 32 and quench resistor device 33 is connected to an input terminal of the inverter 34 .
  • the quench resistor device 33 is disposed to be closer to the power source than the avalanche photodiode 32 is, and is connected to the power source.
  • the avalanche photodiode 32 which is disposed to be closer to the ground line than the quench resistor device 33 is, is connected to be reverse-biased between the power source and the ground line.
  • Each light receiver 31 configured above is also called a single photon avalanche photodiode (SPAD).
  • the light receiver array 30 is designed as a silicon photo multiplier (SiPM) that is comprised of the light receivers 31 arranged in an array.
  • SiPM silicon photo multiplier
  • Each light receiver 31 is configured to operate in a Geiger mode to output a pulse signal to the sum calculator 40 with a constant probability in response to receiving a photon of reflected light from the target object OB. That is, a pulse signal outputted from any light receiver 31 represents that reflected light from the target object OB is incident on the corresponding light receiver 31 .
  • a pulse signal outputted from each light receiver 31 has a second pulse width PW 2 that is previously determined to be more than or equal to the first pulse width PW 1 .
  • the sum calculator 40 is configured to receive the pulse signals outputted substantially simultaneously from at least some of the light receivers 31 and calculates, as a pulse-number sum, the number of the received pulse signals. Then, the sum calculator 40 is configured to output the calculated pulse-number sum to the histogram generator 50 .
  • the histogram generator 50 is configured to generate a histogram based on the pulse-number sum outputted from the sum calculator 40 .
  • FIG. 3 illustrates an example of the histogram generated by the histogram generator 50 .
  • the histogram has a horizontal axis representing class intervals; each of the class intervals shows a corresponding value of time of flight (TOF) that is defined as time between the emitting of a corresponding laser light pulse and the receiving of reflected light based on the emitted laser light pulse.
  • TOF time of flight
  • the histogram also has a vertical axis representing, as a frequency, a value of the pulse-number sum calculated by the sum calculator 40 ; the value of the pulse-number sum represents an intensity of the reflected light from the target object OB.
  • the histogram generator 50 records the value of the pulse-number sum outputted from the sum calculator 40 every recording period that is synchronized with the period at which the laser light pulse is emitted from the light source 20 , thus generating the histogram.
  • a selected frequency in the frequencies of the histogram which corresponds to a selected class interval in the class intervals of the histogram, will become larger; the selected class interval corresponds to a time of reflected light from the target object OB being incident on the light receiver array 30 . That is, if there is a larger class interval in the class intervals of the histogram, it will be possible to calculate the distance to the target object OB in accordance with the time corresponding to the larger class interval.
  • the histogram generator 50 can be configured to transmit the laser light pulse several times for generation of one histogram, and integrate the pulse-number sums, i.e. frequencies, obtained based on the transmitted laser light pulses to thereby generate one histogram. This configuration enables a signal-to-noise ratio (S/N ratio) of the generated histogram to be improved.
  • S/N ratio signal-to-noise ratio
  • the peak detector 60 which is illustrated in FIG. 1 , is configured to detect, in the histogram generated by the histogram generator 50 , a peak edge point tpk that represents an end point, i.e. a falling-edge point, of a peak figure (see FIG. 3 ). Peaks in the histogram according to the first embodiment each represent a frequency at a corresponding class interval, which is higher than a predetermined frequency threshold. The peak figure represents the assembly of adjacently successive peaks in the histogram, which has a substantially crest configuration.
  • the peak figure is comprised of frequencies that sequentially increase over time, so that a selected class interval corresponding to the last frequency of the peak figure immediately before a next decreased frequency in the histogram is defined as the peak edge point tpk illustrated in FIG. 3 .
  • the distance calculator 70 is configured to subtract, from the time, i.e. the value of the TOF, of the peak edge point tpk, a time length of the second pulse width PW 2 to thereby calculate a light incident time tin.
  • the distance calculator 70 is additionally configured to calculate a distance D to the target object OB relative to the apparatus 10 based on the calculated light incident time tin.
  • ⁇ t represents the calculated time length
  • c represents the speed of light
  • the distance calculator 70 is configured to output the calculated distance D to, for example, an unillustrated ECU installed in the vehicle.
  • the ECU installed in the vehicle is configured to detect obstacles and/or perform cruise assistance of the vehicle in accordance with the distance D.
  • FIG. 4 illustrates three histograms respectively generated based on three different intensity levels of reflected light that is incident on the light receiver array 30 .
  • the histogram based on the highest intensity level of reflected light incident on the light receiver array 30 will be referred to as a highest-intensity histogram
  • the histogram based on the medium intensity level of reflected light incident on the light receiver array 30 will be referred to as a middle-intensity histogram
  • the histogram based on the lowest intensity level of reflected light incident on the light receiver array 30 will be referred to as a lowest-intensity histogram.
  • the frequency of a histogram generated by the histogram generator 50 immediately after the light incident time tin that represents reflected light incident timing on the light receiver array 30 becomes higher as the intensity level of the reflected light incident on the light receiver array 30 becomes higher. This is because, the higher the intensity level of reflected light incident on the light receiver array 30 , the larger the number of light receivers 31 in the light receiver array 30 , which substantially simultaneously output pulse signals, resulting in the pulse-number sum being larger.
  • the lower the intensity level of reflected light incident on the light receiver array 30 the smaller the number of light receivers 31 in the light receiver array 30 , which substantially simultaneously output pulse signals, resulting in the frequencies of the histogram being smaller.
  • the optical distance measuring apparatus 1 is configured to subtract, from the time of the peak edge point tpk, the time length of the second pulse width PW 2 to thereby calculate the light incident time tin, and calculate the distance D to the target object OB as a function of the light incident time tin.
  • the second pulse width PW 2 to be outputted from each light receiver, i.e. each light receiving element, 31 is set to be longer or equal to the first pulse width PW 1 of a laser light pulse to be emitted from the light source 20 , which can be expressed by the following equation PW 2 PW 1 .
  • This configuration of the apparatus 1 enables the duration of light, i.e. the width of pulsed light, reflected from the target object OB and incident on at least one light receiver 31 , which substantially corresponds to the first pulse width PW 1 , to be constantly shorter or equal to the second pulse width PW 2 of a pulse signal outputted from the at least one light receiver 31 in response to the incident of the reflected light on the at least one light receiver 31 .
  • the time length of the second pulse width PW 2 therefore enables the light incident time tin that represents reflected light incident timing on the light receiver array 30 to be constantly calculated.
  • FIG. 4 shows that, like the peak edge point tpk, the reflected light incident timing tin is kept unchanged independently of the intensity level of the reflected light incident on the light receiver array 30 .
  • the optical distance measuring apparatus 1 calculates the incident timing tin of reflected light incident on the light receiver array 30 with higher accuracy, making it possible to measure, based on the incident timing tin, the distance D to the target object OB with higher accuracy even if a reflection rate of the target object OB and/or ambient light have an impact on the intensity level of reflected light incident on the light receiver array 30 of the apparatus 1 .
  • the first embodiment describes an example that a histogram generated by the histogram generator 50 has a single peak figure, i.e. a single peak shape. Note that, as illustrated in FIG. 5 , a histogram generated by the histogram generator 50 has plural peak figures due to, for example, ambient light.
  • the peak detector 60 is configured to detect, in the histogram generated by the histogram generator 50 , plural peak figures, and detect, from each peak figure, a peak edge point tpk that represents an end point of the corresponding peak figure (see FIG. 5 ).
  • the distance calculator 70 according to the second embodiment is configured to select one of the peak figures; the selected one of the peak figures has a larger width than widths of any other peak figures.
  • the distance calculator 70 of the second embodiment is additionally configured to calculate the distance to the target object OB as a function of the peak edge point tpk of the selected one of the peak figures.
  • the distance calculator 70 can be configured to
  • the apparatus 1 configured to calculate the distance to the target object OB based on the peak edge point tpk of the selected one of the peak figures, which has a larger width than a width of another of the peak figures, thus inhibiting calculation of the distance to the target object OB using a false peak figure generated due to, for example, ambient light.
  • the distance calculator 70 can be configured to calculate distance candidates to the target object based on the respective peak figures, and output the calculated distance candidates to the ECU installed in the vehicle.
  • the ECU can be configured to determine which of the distance candidates is an actual distance to the target object OB in accordance with predetermined reference information. For example, the ECU can be configured to determine one of the distance candidates as the actual distance to the target object OB; the determined one of the distance candidates is the closest to a previously determined actual distance to the target object OB.
  • the peak detector 60 of each of the first and second embodiments is configured to compare the frequencies of the histogram generated by the histogram generator 50 with the predetermined frequency threshold to thereby detect at least one peak figure in the histogram.
  • the peak detector 60 of the third embodiment is configured to compare the shape of the histogram generated by the histogram generator 50 with previously prepared tentative peak figure templates to thereby detect at least one peak figure in the histogram.
  • the peak detector 60 of the third embodiment is configured to store template data including the previously prepared tentative peak figure templates in a memory of the apparatus 10 .
  • the peak detector 60 is additionally configured to perform a known template-matching approach for the histogram and the template data to thereby extract at least one portion that substantially matches at least one of the tentative peak figure templates, thus determining the extracted at least one portion in the histogram as at least one peak figure.
  • This configuration inhibits calculation of the distance to the target object OB using a false peak figure generated due to, for example, ambient light.
  • the optical distance measuring apparatus 10 of the fourth embodiment is further comprised of an adjuster 80 (see FIGS. 7 , 9 , and 10 ) for maintaining that the first pulse width PW 1 and the second pulse width PW 2 constantly have the following relationship:
  • the adjuster 80 is configured to measure the second pulse width PW 2 of the pulse signal outputted from each of at least some of the light receivers 31 , and change at least one of the first pulse width PW 1 and the second pulse width PW 2 to thereby adjust the second pulse width PW 2 to be longer or equal to the first pulse width PW 1 .
  • the adjuster 80 can be designed as an electronic circuit or a programmable software module.
  • FIG. 7 schematically illustrates a first example of the adjuster 80 .
  • a first adjuster 80 a as the first example of the adjuster 80 is configured to change a resistance value Rq of a quenching resistor connected to the avalanche photodiode 32 included in each light receiver 31 to thereby adjust the second pulse width PW 2 of a pulse signal outputted from the corresponding light receiver 31 .
  • the first adjuster 80 a includes a pulse width measurement unit 81 , and a quenching resistor circuit 82 in place of the quenching resistor device 33 ;
  • the quenching resistor circuit 82 can be comprised of, for example, a transistor, such as an FET.
  • FETs each have linear characteristics in which a drain current varies in proportion to a gate voltage Vg applied to the gate of the corresponding transistor. This enables adjustment of the gate voltage Vg applied to the gate of a transistor to serve the quenching resistor circuit 82 as a voltage-controlled variable resistor.
  • the pulse width measurement unit 81 is configured to measure the riding timing and falling timing of each of the pulse signals outputted from the light receiver 31 every predetermined sampling period, and calculate an elapsed time from the rising timing to the falling timing of each of the pulse signals as the second pulse width PW 2 for the corresponding one of the pulse signals.
  • the pulse width measurement unit 81 is additionally configured to change the gate voltage Vg to be applied to the quenching resistor circuit 82 to thereby change the resistance value Rq of the quenching resistor circuit 82 , thus adjusting that the calculated second pulse width PW 2 is longer or equal to the first pulse width PW 1 of a laser light pulse that will be emitted from the light source 20 .
  • FIG. 8 schematically shows an example of the relationship between an input voltage to the inverter 34 of the light receiver 31 and an output voltage from the inverter 34 thereof. Specifically, the top part of FIG. 8 illustrates how the input voltage to the inverter 34 , which will be referred to as V 1 , is changed over time, and the bottom part of FIG. 8 illustrates how the output voltage from the inverter 34 , which will be referred to as V 1 out, is changed over time.
  • the input voltage V 1 to the inverter 34 decreases abruptly from a bias voltage level Vb applied to the light receiver 31 down to a breakdown voltage Vbd. This causes the output voltage V 1 out from the inverter 34 to rise from a low level to a high level. Thereafter, the input voltage V 1 to the inverter 34 has been recovered up to the bias voltage Vb.
  • the output voltage Vout 1 from the inverter 34 falls down from the high level to the low level.
  • the value Rq of the quenching resistor of the light receiver 31 which is configured to operate set forth above, enables the recovery speed of the input voltage V 1 to the inverter 34 from the breakdown voltage Vbd to be changed, making it possible to change the pulse width of the output voltage V 1 out from the inverter 34 , which serves as the second pulse width PW 2 .
  • the first adjuster 80 a is configured to adjust the second pulse width of a pulse signal outputted form each light receiver 31 to automatically maintain the following relationship between the first pulse width PW 1 and the second pulse width PW 2 even if the first pulse width PW 1 and/or the second pulse width PW 2 are changed depending on the temperature dependency characteristics of the laser diode device 21 and/or light receiver 31 :
  • FIG. 9 schematically illustrates a second example of the adjuster 80 .
  • a second adjuster 80 b as the second example of the adjuster 80 is configured to
  • the second adjuster 80 b includes a pulse width measurement unit 81 , and a comparator 83 in place of the inverter 34 .
  • a voltage V 1 outputted from the avalanche photodiode 32 is inputted. More specifically, to the comparator 83 , a voltage V 1 at the connection point between the quenching resistor device 33 and the avalanche photodiode 32 is inputted.
  • the comparator 83 is configured to compare the voltage V 1 with the reference threshold voltage Vth outputted from the pulse width measurement unit 81 .
  • the comparator 83 is additionally configured to
  • the pulse width measurement unit 81 of the second adjuster 80 b is configured to vary the reference threshold voltage Vth inputted to the comparator 83 to thereby automatically maintain that the first pulse width PW 1 and the second pulse width PW 2 constantly have the following relationship even if the first pulse width PW 1 and/or the second pulse width PW 2 are changed depending on the temperature dependency characteristics of the laser diode device 21 and/or light receiver 31 :
  • FIG. 10 schematically illustrates a third example of the adjuster 80 .
  • a third adjuster 80 c as the third example of the adjuster 80 includes a pulse width measurement unit 81 .
  • the light source 20 includes a driver 84 for driving the laser diode device 21 , and the pulse width measurement unit 81 is connected to the driver 84 . That is, the driver 84 is configured to drive the laser diode device 21 to cause the laser diode device 21 to transmit laser light pulses each having the first pulse width PW 1 .
  • the pulse width measurement unit 81 is configured to measure the second pulse width PW 2 of each of the pulse signals outputted from the light receiver 31 as set forth above.
  • the pulse width measurement unit 81 is additionally configured to control the driver 84 to thereby adjust the first pulse width PW 1 of a laser light pulse that will be emitted from the laser light device 21 , thus maintaining the measured second pulse width PW 2 to be longer or equal to the first pulse width PW 1 .
  • the pulse width measurement unit 81 is additionally configured to control the driver 84 to thereby adjust the falling timing of a first pulse signal for a laser light pulse that will be emitted from the laser light device 21 , thus maintaining the measured second pulse width PW 2 to be longer or equal to the first pulse width PW 1 .
  • the third adjuster 80 c is configured to automatically maintain the following relationship between the first pulse width PW 1 and the second pulse width PW 2 even if the first pulse width PW 1 and/or the second pulse width PW 2 are changed depending on the temperature dependency characteristics of the laser diode device 21 and/or light receiver 31 :
  • the adjuster 80 according to the fourth embodiment can be configured as the combination of at least two of the first to third adjusters 80 a to 80 c . That is, the adjuster 80 according to the fourth embodiment can be configured to adjust at least two of (i) the resistor of the quenching resistor circuit 82 , (ii) the reference threshold voltage Vth inputted to the comparator 83 , and (iii) the falling timing of the first pulse signal, thus maintaining that the first pulse width PW 1 and the second pulse width PW 2 constantly have the following relationship:
  • FIG. 11 illustrates a modified configuration of the light receiver 11 .
  • the light receiver 31 according to the first embodiment is configured such that the avalanche photodiode 32 , which is disposed to be closer to the ground line than the quenching resistor device 33 is, is connected to the ground line, and the quenching circuit is connected to the power source.
  • a light receiver 31 b according to the modified configuration is configured such that the avalanche photodiode 32 , which is disposed to be closer to the power source than the quench resistor device 33 is, is connected to be reverse-biased between the power source and the ground line.
  • the light receiver 31 b is additionally configured such that the quenching resistor device 33 is connected to the ground line.
  • a buffer circuit 36 is connected to the connection point between the avalanche photodiode 32 and quenching circuit 33 .
  • FIG. 12 schematically shows an example of the relationship between an input voltage V 2 to the buffer circuit 36 of the light receiver 31 b and an output voltage V 2 out from the buffer circuit 36 thereof. Specifically, like the light receiver 31 illustrated in FIG. 2 , FIG. 12 shows that the above configuration of the light receiver 31 b illustrated in FIG. 11 enables the light receiver 11 to generate a pulse signal.
  • the quenching resistor device 33 is comprised of a variable resistor, such as a transistor. This configuration of the quenching resistor device 33 enables the second pulse width PW 2 to be adjusted in the same approach as that described in the fourth embodiment based on FIGS. 7 and 8 .
  • the optical distance measuring apparatus 10 is comprised of the plurality of light receivers 31 but can be comprised of a single light receiver 31 .
  • the optical distance measuring apparatus 10 according to this modification is preferably configured to transmit the laser light pulse several times for generation of one histogram, and integrate the pulse-number sums, i.e. frequencies, obtained based on the transmitted laser light pulses to thereby generate one histogram.
  • the second pulse signals illustrated in some figures in the above embodiments are each configured as an active-high signal, in other words, a positive pulse signal, but can be each configured as an active-low signal, in other words, a negative pulse signal.
  • the present disclosure is not limited to the embodiments described herein but can be implemented by various configurations within the scope of the present disclosure.
  • one or some technical features disclosed in the above embodiments can be replaced with other technical features or combined with each other to solve a part or all the above problem or to achieve at least one of or all of the above benefits. If at least one of the technical features disclosed in the above embodiments is not described as an essential component, the at least one of the technical features can be emitted.

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  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
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US17/061,239 2018-04-04 2020-10-01 Optical distance measuring apparatus Active 2041-04-20 US11933896B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2018-072108 2018-04-04
JP2018072108A JP6741039B2 (ja) 2018-04-04 2018-04-04 光測距装置
PCT/JP2019/013168 WO2019194039A1 (ja) 2018-04-04 2019-03-27 光測距装置

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Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11796649B2 (en) * 2019-10-28 2023-10-24 Microvision, Inc. Method and device for optically measuring distances
JP7562570B2 (ja) 2020-01-10 2024-10-07 ソニーセミコンダクタソリューションズ株式会社 受光装置および測距装置
TW202205687A (zh) * 2020-06-12 2022-02-01 日商索尼半導體解決方案公司 光檢測電路及測距裝置
US12117313B2 (en) 2021-02-25 2024-10-15 Sony Semiconductor Solutions Corporation Photodetection device and photodetection system
CN113608230A (zh) * 2021-08-03 2021-11-05 汤恩智能科技(常熟)有限公司 测距方法、装置及设备
WO2023189856A1 (ja) * 2022-03-29 2023-10-05 パナソニックＩｐマネジメント株式会社 固体撮像装置
WO2024202651A1 (ja) * 2023-03-30 2024-10-03 ソニーセミコンダクタソリューションズ株式会社 光検出装置および測距システム

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5243553A (en) 1991-07-02 1993-09-07 Loral Vought Systems Corporation Gate array pulse capture device
US5523835A (en) 1993-03-02 1996-06-04 Mitsubishi Denki Kabushiki Kaisha Distance measuring equipment
US6088085A (en) 1997-02-05 2000-07-11 Sick Ag Range measurement apparatus
JP2010072699A (ja) 2008-09-16 2010-04-02 Nikon Corp 画像分類装置および画像処理装置
US20130175435A1 (en) * 2012-01-09 2013-07-11 Stmicroelectronics (Grenoble 2) Sas Device for detecting an object using spad photodiodes
US20140103196A1 (en) * 2012-10-16 2014-04-17 Kabushiki Kaisha Toyota Chuo Kenkyusho Light detector
JP5644294B2 (ja) 2010-09-10 2014-12-24 株式会社豊田中央研究所 光検出器
US20160033644A1 (en) 2014-07-31 2016-02-04 Stmicroelectronics (Research & Development) Ltd. Time of flight determination
JP2016176750A (ja) 2015-03-19 2016-10-06 株式会社豊田中央研究所 光学的測距装置
JP2017161321A (ja) 2016-03-09 2017-09-14 株式会社リコー 回路装置、光検出器、物体検出装置、センシング装置、移動体装置、信号検出方法及び物体検出方法
US20180164415A1 (en) * 2016-12-12 2018-06-14 Sensl Technologies Ltd Histogram Readout Method and Circuit for Determining the Time of Flight of a Photon
US20180253404A1 (en) * 2017-03-01 2018-09-06 Stmicroelectronics (Research & Development) Limited Method and apparatus for processing a histogram output from a detector sensor

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1110398A (zh) * 1993-12-27 1995-10-18 现代电子产业株式会社 光学测距装置及其方法
EP1382979B1 (en) * 2001-04-25 2008-03-05 Nikon Corporation Range finder, range finding method, and photoelectric transducing circuit
JP4832720B2 (ja) * 2004-01-29 2011-12-07 株式会社トプコン パルス信号の処理装置、パルス信号の処理方法およびプログラム
JP4761751B2 (ja) * 2004-10-06 2011-08-31 株式会社トプコン 距離測定装置
JP4395433B2 (ja) * 2004-11-18 2010-01-06 太陽誘電株式会社 光情報記録装置および方法および信号処理回路
JP5206297B2 (ja) * 2008-10-07 2013-06-12 トヨタ自動車株式会社 光学式測距装置及び方法
CN104685866B (zh) * 2012-07-27 2018-12-14 歌乐株式会社 三维物体检测装置以及三维物体检测方法
GB2520232A (en) * 2013-08-06 2015-05-20 Univ Edinburgh Multiple Event Time to Digital Converter
CN103926590B (zh) * 2014-04-01 2016-03-30 中国科学院合肥物质科学研究院 一种不等间距的激光多脉冲测距方法及其测距装置
JP6852416B2 (ja) * 2016-03-10 2021-03-31 株式会社リコー 距離測定装置、移動体、ロボット、装置及び３次元計測方法
CN107015234B (zh) * 2017-05-19 2019-08-09 中国科学院国家天文台长春人造卫星观测站 嵌入式卫星激光测距控制系统
WO2018235944A1 (ja) * 2017-06-22 2018-12-27 株式会社デンソー 光測距装置

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5243553A (en) 1991-07-02 1993-09-07 Loral Vought Systems Corporation Gate array pulse capture device
US5523835A (en) 1993-03-02 1996-06-04 Mitsubishi Denki Kabushiki Kaisha Distance measuring equipment
US6088085A (en) 1997-02-05 2000-07-11 Sick Ag Range measurement apparatus
JP2010072699A (ja) 2008-09-16 2010-04-02 Nikon Corp 画像分類装置および画像処理装置
JP5644294B2 (ja) 2010-09-10 2014-12-24 株式会社豊田中央研究所 光検出器
US20130175435A1 (en) * 2012-01-09 2013-07-11 Stmicroelectronics (Grenoble 2) Sas Device for detecting an object using spad photodiodes
US20140103196A1 (en) * 2012-10-16 2014-04-17 Kabushiki Kaisha Toyota Chuo Kenkyusho Light detector
US20160033644A1 (en) 2014-07-31 2016-02-04 Stmicroelectronics (Research & Development) Ltd. Time of flight determination
JP2016176750A (ja) 2015-03-19 2016-10-06 株式会社豊田中央研究所 光学的測距装置
JP2017161321A (ja) 2016-03-09 2017-09-14 株式会社リコー 回路装置、光検出器、物体検出装置、センシング装置、移動体装置、信号検出方法及び物体検出方法
US20180164415A1 (en) * 2016-12-12 2018-06-14 Sensl Technologies Ltd Histogram Readout Method and Circuit for Determining the Time of Flight of a Photon
US20180253404A1 (en) * 2017-03-01 2018-09-06 Stmicroelectronics (Research & Development) Limited Method and apparatus for processing a histogram output from a detector sensor

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